Antenna



FIG. 1 is a left side elevation view of an antenna showing our new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a right side elevation view thereof;

FIG. 4 is a rear elevation view thereof; and,

FIG. 5 is a bottom plan view thereof, the top plan view being a mirror image thereof.

The broken line showing of an environmental mounting structure in FIGS. 1 and 3 is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for an antenna, as shown and described. 